The characteristics of electromagnetic modes that are driven by ion distributions with a drift relative to the electron distribution in the presence of a two-component magnetic field are identified under finite-&bgr; conditions for both the ion and the electron distribution. The rate of momentum transfer from the ion to the electron population, where a current is induced, is evaluated. The relevance of this mode to a model suggested for the interpretation of the structure of the Uranus bow shock is pointed out. ¿ American Geophysical Union 1992